Abstract: A breath actuated inhalation device having a housing having a passageway for the passage of air therethrough. The passageway, of relatively small diameter, opens into an emptying chamber, of relatively greater diameter, adjacent that end of the housing which is adapted for insertion into the mouth or nose of the user. Adjacent that end of the emptying chamber closest to the passageway, the device has means for receiving and opening a unit dose of powdered medicament for administration. During inhalation, a portion of the air stream passing through the passageway into the emptying chamber is deflected by a beveled deflector causing sufficient air flow to come into contact with the powdered medicament whereby the powdered medicament is entrained in the air stream being inhaled, and is carried into the nose, throat or lungs of the user where beneficial or therapeutic action of the medicament occurs.